6533b826fe1ef96bd1283aeb

RESEARCH PRODUCT

Location of the mean-field critical temperature of underdopedYBa2Cu3Oyfilms

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description

We determined the Berezinskii-Kosterlitz-Thouless transition temperature ${T}_{\mathit{KT}}$ at the superconducting layer level and the mean-field critical temperature ${T}_{c0}$ in oxygen-deficient $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{y}$ films ($y\ensuremath{\sim}6.5$, 6.55, and 6.65). We used the $T$ dependence of the quasi-two-dimensional $I\text{\ensuremath{-}}V$ exponent for $T\ensuremath{\leqslant}{T}_{\mathit{KT}}$, and the analysis of the resistive transition in the framework of the Ginzburg-Landau two-dimensional Coulomb gas model for $Tg{T}_{\mathit{KT}}$. Both procedures give essentially the same results, with ${T}_{c0}$ remaining in the domain of the electrical resistivity drop.